Benders'dictionary of nutrition and food technology

91are not digested, and should be considered among the unavailablecarbohydrates.Larger polymers of carbohydrates are known as polysaccharidesor complex carbohydrates. Nutritionally two classes ofpolysaccharide can be distinguished: (a) starches, polymers ofglucose, either as a straight chain (amylose) or with a branchedstructure (amylopectin); (b) a variety of other polysaccharideswhich are collectively known as non-starch polysaccharides(NSP) and are not digested by human digestive enzymes. Thecarbohydrate reserve in liver and muscles is glycogen, a glucosepolymer with the same branched structure as amylopectin.The metabolic energy yield of carbohydrates is 17 kJ (4 kcal)/g.More precisely, monosaccharides yield 15.7 kJ (3.74 kcal),disaccharides 16.6 kJ (3.95 kcal) and starch 17.6 kJ (4.18 kcal)/g.glycerol is a three-carbon sugar alcohol, and is classified as acarbohydrate; it yields 18.1 kJ (4.32 kcal)/g.See also starch; sugar; sugar alcohols.CARBOHYDRATES: MONO- AND DISACCHARIDES